The mysterious Lexus LFA AD-X prototype has been spotted again on the Nürburgring, six months after its last public appearance:

The AD-X is one of three LFA prototypes (see: AD-A & AD-B) that have been testing at Nürburgring over the past year — it’s been confirmed that all three are advanced development one-off vehicles, and not an indication that a special edition LFA is in the works.

(The big question: what kind of advanced development are these LFAs testing?)